Removal of tar acids from ammonia liquor and other liquors



Dec. 27, 192 7. 1,653,783

H. W. ROBINSON ET AL REMOVAL OF TAR ACIDS FROM AMMONIA LIQUOR AND OTHERBIQUORS Filed June 25. 1926 $0. 4: baa MM ZZWK'NEYS MWORS Patented Dec.27, 1927.

UNITED STATES PATENT orncs.

HERBERT WILLIAM RO BINS ON 0] BIRMINGHAM, AND DERIC WILLIAM PARKES, OFWEST BROMWICH, ENGLAND.

REMOVAL or TAR Acrns r'nom AMmoNrA LIQUOR AND ornnn LIQUORS.

Application filed June 2a, 1926, semi'no. 117,982, and in Great BritainAugust 7, 1925.

This invention relates to an improved process and apparatus for removingand recovering tar acids larly for removing and rec amounts of tar acidsfrom large of liquor.

According from liquors and particuovering small quantities to thepresent invention, the

ammonia liquor is acidified, and subsequently carbon, it beingdesirable, of

brought into contactwith activated course, to allow any sludge presentto be deposited after the acidifying treatment. The acidification may becarried out bysaturatlng the liquor with carbon dioxide or by means ofmineral acid. The tar acids are removed from the carbon, preferably byheating the carbon under reduced pressure or in a current of superheatedsteam; or nation of these. carbon dioxide and flue used instead ofsteam. After by means of a combi- Gases such as nitrogen, gases may bealso removing the tar acids, it is advisable to cool the carbon in acurrent of inert gas.

The whole process may b e carried out either as a batch process or as acontinuous process, and in order that the invention may be clearlyunderstood and readily carried its into effect, a process of each ofthese types will now be described as examples of processes in accordancewith the invention.

In carrying out an example of a batch process, 1000 cos. of ammonialiquor containing 0.421 per cent of tar acids are saturated with carbondioxide gas and allowed to stand until the preclpitated solids havesettled. The clear liquor 1s then agitated for one hour with 50 gms. of

activated carbon.

The carbon is filtered off and the tar acids removed by heating thecarbon at 370600 C.

in a current of steam superheated to about 300 0. After removal carbonis cooled in a current of the tar acids the of carbon dioxide. Thecarbon is now transferred to a fresh batch of liquor and the peatedrAfter 18 been thus treated it is found process is relitres of the aboveliquor have that 96.85 per cent of the total tar acids present have beenremoved from the liquor and of the tar acids so removed 80.86 per centhave been recovered. If the process is continued by apply ing the carbonto a further 1000 ccs. of liquor it is found that the carbon will stillremove over 90 per cent of present in this liquor.

the tar acids vated carbon and are connected. together in series bymeans of pipes 5, the top of one chamber being connected to. the bottomof the next in the series as shown in the drawings. The top of the lastchamber numbored 4: is connected by a pipe 6 to the first chambernumbered 1 of the series. The bottom of each chamber is provided with athree-way valve, these being numbered PA and are connected to a liquorsupply pipe 7, and by means of which the liquor may be passed directinto the bottom of any one of the chambers. The top of each chamber issimilarly provided with a three-Way valve,

these being numbered 1L4", and by means chamber'll. Theoutlet end of thecoil .10

leads into a collecting vessel 12 for the tar acids. The chambers 14 areprovided with perforated rings 13 connected through valves 14; to asteam supply pipe 15, and with jackets 16 by means of which the chambersmay be heated externally. In the drawings, the ackets 16 are shownsupplied with hot gas such as flue gas at the bottom of each from acommon inlet pipe 17, the inlet to each jacket beingindependently;controlled by valves 18. The gases from the jackets 16 aretaken off through a common outlet pipe 19, each outlet also beingindependently controlled by valves 20. Suitable grids 21 are disposedabove and below the activated carbon in the 10 chambers. A,

When carrying out a continuous process, prevlously acidified and settledliquor is admitted to the pipe 7 and with the valves ositioned as shownin. the drawings, the 105 iquor is admitted to the bottom'f of thesecond chamber 2 of the series," and'fiowing upwards through thischamber passes through the corres onding pipe 5 into the bottom of thenext 0 amber of the series, and so on to no the last chamber. From thelast chamber, the liquor flows into the outlet pipe 8. The liquor is.admitted to the chambers 2, 3 and 1 at such a speed that the eflluent,liquor contains no tar acids, these having all been absorbed by theactivated carbon contained in these chambers. During the time that theliquor is being admitted to chambers 2, 3

tion with the condenser coil 10 and the valve 1 is closed completely.When all the tar acids have been removed from the carbon in chamber 1,the steam supply is cut off by operating the valve 14 of this chamberand the chamber connected up in series with the other chambers, chamber2 now being cut out of the series and the tar acids re moved from thecarbon, in this latter chamber. To effect this operation, valve .1 isturned so as to cut off communication with the condenser 10 and toestablish communication with the outletpipe 8. The valve 1 is operatedso as to connect chamber 1 with the pipe 6, while the valves 2 and 1"are closed altogether. Finally, valve 2* is opened to the condenser 10through the pipe 9 and the valve 3 opened to the pipe 7. superheatedsteam is now passed through the valve'14 of chamber 2 and the carbonheated through the external jacket 16 of this chamber, the tar acidsbeing thus removed and carried ofi to the condenser 10. During thissteaming-out process, the liquor is being admitted to the bottom ofchamber 3 and flows through pipe 5 to the bottom of chamber 4, and fromthe top of this latter chamber through the pipe 6 to the bottom ofchamber 1. As valve 1 is now opened to the outlet pipe 8, the liquor nowflows out through this pipe. This se-- uence of operations is repeatedfor each of t e chambers in turn, and it is thus seen that asimultaneous absorbingand removal of the tar acids is being continuallyeifected. After each steaming-out process, the chamher through which thesteam has been passing is cooled before being connected up again to theother chambers of the series. Instead of steaming-out the tar acids'fromthe carbon while this latter is in the chambers, the carbon may beremoved to a separate still or retort and the tar acids then removedfrom the carbon.

An example of the operation of such an apparatus will now be given. 61litres of liquor containing .421 per cent of tar acids are subjected-tothe preliminary treatment including acidification as described above andpassed through the apparatus containmg 150 gms. of carbon at an averagespeed of 1.89 litres per hour. The liquor is completely freed from taracids and 81.8 per cent of the tar acids removed by the carbon arerecovered.

Ordinary commercial activated carbon may contain iron compounds and ithas been found advantageous to remove such compounds by giving thecarbon a preliminary treatment with acid. The carbon is then washed withwater and heated under reduced pressure in a current of superheatedsteam or inert gas.

Having thus described our invention, What we claim as new and desire tosecure by Letters Patent is d 1. A process for removing tar acids fromammonia liquor, which consists in acidifying the liquor and thenbringing the liquor into contact with activated carbon.

2. A continuous process for removing tar acids from ammonia liquor,which consists.

in acidifying the liquor, admitting the said liquor to the bottom ofsome of a number of chambers containing activated carbon and connectedin series to absbrb the tar acids from the said liquor, assing steamthrough the remainder of the chambers and then condensing the tar acidsremoved by the steam.

3. A process for removing tar acids from ammonia liquor, which consistsin saturating the liquor with carbon dioxide gas, agitating the liquorwith activated carbon to absorb the tar acids and removing the tar acidsfrom the carbon by distillation.

4. A process for removing tar acids from ammonia liquor, which consistsin treating the liquor with carbon dioxide gas, agitating the liquorwith activated carbon to absorb the tar acids and distilling off the taracids from the carbon by external heating and by direct contact ofsteam.

5. A process for removing tar acids from ammonia liquor, which consistsin acidifying the liquor, and then bringing the liquor into contact withactivated carbon which has been'heated under reduced pressure, heated inan atmosphere of an inert gas, and then cooled in an atmosphere of aninert gas.

In witness whereof we hereunto subscribe our names this 27th day of May,1926.

-HE-RBERT \VILLIAM ROBIN SG N.

DERIG WILLIAM PARKES.

